System for receiving and recording vibrations



Y Marh 21, 1933. F R|EBER 1,902,183

SYSTEM FOR RECEIVING ANDV RECORDING VIBRATIONS Filed May 24, 1927 IN vEN'roR h Fran/r /F/er `Pamesa Mar. ai, i933 l wam@ narran' stares I'paraat casina FRANK BIEBER, F SAN FRANCISCO, CALIFGRNIA SYSTEM FOB RECEIVING AND RECORDING VIBRATIONS Y Application led ltfay 24, 1927. `Serial No. 193,941.

This invention relates to a system of meassensitized material moving at constant speed. urement, and particularly to the determina- Without the aid of my invention, the record tion of the time required for a shock or vibrafrom each receiver may and usually Would tion, such as may be imparted to the earth,f merge into those of the others, making it to arrive at a given point.. difficult if not impossible to locate the times rlfhis measurement of time is of particular of first arrivalof the mechanical vibrations importance in connection with geophysical at the spaced receivers. With the aid of my explorations. For such purposes, .shocks or invention, each receiver would produce aa vibrations are imparted to the earth, as by definite, easily recognizable record separa-te 1 the use of explosives; and the times ofarrival from the others. .16 after the blast at definite points at a distance Of course it Would be possible to use sepa from the locality of the explosion, are noted. rate recorders for each receiver, making their y From this data, a time-travel curve can be records on a common film. But it is evident plotted; and from this curve can be deduced that this means multiplication of apparatus '-15 other useful information as regards the charwith its attendant increased cost. Further-- acter of theearth strata in the vicinity of the more, it is difficult to build recording apparafield of operation. This mode of exploration tus capable of producing more than a fen is now Well understood and requires no furindependent records on the same film. Act-her description. cordingly it is another object of my inve, It is of course to beunderstood that my to obviate the necessity for all/.such c, A,

invention can as readily be applied to other pleXity. uses, such as for timing the arrival of shocks My invention possesses many other advan-- from guns for locating batteries in war time.- tages, and has Other Objects Which may be When shocks are imparted to the earth by made more easily apparent from a consid-eiaexplosion, it is an observed phenomenon that J1011 0f 011 embdment 0f Iny invention. a succession of mechanical vibratory Waves FOI this purpose I have shown a form in the can be received at a distant point as a result drawing accompanying and forming part of of a single explosion. It is of interest, howthe present Specification. I shall now proever,l only to discover the time of first ar- Cecd to describe this form in detail, which rival. Another object of my invention is to illustrates the general principles of my inmake it possible to suppress all but the first vention; but it is to be understood that this part of the vibrations thus received, so that detailed description is not to be taken in a the record will show only the first group of limitingsense, since the scope of my inven- 5 Waves. In this Way it is entirely feasible to tion is best defined by the appended claims. produce an intelligible single record shovv- Rfeiringto the dravving: ing the times of irstarrival of the mechani- Figure 1 is a facsimile of a record that cal vibrations at increasingly distant points ca n be made of an earth shock in accordance, from the explosion. with the invention described and claimed in 40 In contradistinction to this mode of recordmy copending applicatiomSerial No. 191,212 ,y i ing, the prior systems have-inherent disadfiled June 7 1927, and. entitled Method and if@ vantages, now to be discussed. It has been apparatus for recording explosive shocks possible, for' example, to use a plurality of which has matured into Patent #1,780,567, receivers, located at increasingly distant datedNov. 4, 1930; but Without the aid of points from the explosion for transforming my present invention; this figure being used the mechanical shocks received into electrito show how received vibrations persist for f cal vibrations in any lvvellsknovvn way. Then a long time after their first arrival, and affect each' of these receivers can, be connected to the recorder unless they are rendered inefa common recorder, such as-an oscillograph feet/ive in the manner described herein;

or a tuned string galvanometer, serving to Fig. 2 is a facsimile of a record similar to .trace a photographic record on a strip of that of Fig. 1, but illustrating how, with the i The' vmanner vin vwhich the receiver is' ar- I with the earth. One form of such a piezo crystal device is shown and claimed in my copcuding application, Serial No. 197,211 filed June 7, 1927 and entitled Vibration sensitive systems. It is sufficient for our present purposes however, to note that this device'when aiiected by vibrations, causes corresponding variations in potential differ* ence between the electrodes 18 and 19 that are placed in contact therewith on opposite sides thereof.

In accordance With my invent-ion, these va-A riations in potential difference are amplified by one or more amplifier stages, and I preferaoly ut1l1ze three electrode electronic emis- `l sion devices for this purpose. Such an amplifier (usually termed an audion) 1s shown at 20, and is indicated as including an evacuated vessel 1n which are enclosed an electron emitting device 2l. 1n the form of a heated filament, a plate or anode 22, and a control circuit of tube 29 includes a B battery 34 and connects to a modulator 35 that can be built yin accordance with my invention disclosed in the patent heretofore referred to. This modulator causes the vibratory-current to assume the compound Wave forms of Figs. 1 and 2, facilitating the interpretation of the record. Thence, the oscillations are impressed upon any desirable recorder 36, as through transformer 51.

It no further element-s were included in the system, it is evident that persistinar vibrations affecting device 17 would all be recorded.

However, I arrange further elements in suchr a Way that soon after oscillations start, they cause an automatic blocking of tube 29 so that it can no longer transmit energy to recorder 36. This can be done by impressing a'suiiiciently large negative potential upon grid 31, relative to filament 30. I shall now describe how such a potential is built up by the oscillations themselves.

An amplifier tube 37 is arranged to be aftected by the output circuit of tube in a manner ventirely similar to the arrangement just described in connection with tube 29. Thus the grid 38 otthis tube is connected through stopping condenser 39, With the plate 22 of tube 20. The output circuit of l y: i l re thuis; caused to affect tube 29." The out'-'y put lbridged across an adJustable leak resistancev tube 37 includes plate 43, primary 40 of transformer 41, B battery 25, and filament 42. The transformer 41 serves to transmit the am- `jplified vibrations to a rectiiier device 43, such 47 suiiciently high so as to cause lcondenser 46 to retain its charge for a short time. The condenser 46 thus serves to integrate the energy transmitted to it through tube 43. TheY potential difference existing across this condenser is available as a grid bias `for tube 29; and when the charging of condenser 46 is suiicient, the grid bias is large enough to block tube 29 completely. The grid biasing circuit consists of batteries 27 and 48 and condenser 46. Battery 48. is of such value that when the condenser 46 is uncharged, its negative potential transmitted through resistance 47 to grid 31 is suicient to produce eicie'nt ampli cation by tube 29. However, as device 17 is continued to be energized by the earth waves, condenser 46 becomes more and more charged; and since its potential is added tothe battery 48, in a short time this charge is suiiicient to produce complete blocking of tube 29, and prevention of transfer of energy to recorder 36. When the persistent vibrations cease, the condenser 46 discharges through resistance 47, and the apparatus is thus automatically restored to active condition, and is ready to respond to a succeeding disturbance. By proper adjstment of resistance 47, the interval of interruption of energy transfer between devices 17 and recorder 36 maybe set at a' desired value.

The recorder 36 can be iniuenced by other receivers operating substantially as that already described, but placed at a diierent distance from the explosion. One such additional receiver is diagrammatically indicated at 49, which transmits vibrations to recorder 36 through transformer 50. This recorder can produce a common non-interfering recordv from all of these receiver circuits.

I claim: y

1. In a system of the character described, means fortransmitting electrical vibrations, means for recording said vibrations, means responsive to the same vibrations for building upa potential difference, and means utilizing said potential difference for blocking said transmitting means.

2. In a system of the character described, an electronic emission device having a control electrode and an electron emitting electrode, for transferring electrical vibrations, means for conducting vibrations thereto. means affected by the same vibrations for building up a potential diiference, and means .whereby said potential difference is applied between the control electrode and the electron emitting electrode to block said electronic emission device after an interval sucient to produce the potentialdiference.

3. The combination as set forth in claim 2, with the addition of means for adjusting the interval during which said device is blocked. 4. Ina system of the character described, an electronic emission amplifier device having'a control electrode and an electronemitting electrode, for transferring electrical vibratorv energy, means for conducting vibrations "thereto, means including a rectifier and a condenser for building up across the condenser terminals, a potential difference by the aid of successive charges derivedfrom the said conducting means, and means whereb v said potential difference is impressed between the control electrode and the electron emitting electrode to block said electron emission amplifier after an interval and=thus to prevent its transferring energy.

5. In a system for recording earth vibrations at a plurality of spaced points., a receiver for converting` the vibrations into recordable form located at each ofsaid points. a. common recorder affected by all'of said receivers. and means ensuring that the impulses received bv the receivers do notV overlap in the recorder. comprising means limiting the interval of energy transfer between each receiver and the recorder.

6. In a s vstem for recording earth vibrations at a plurality of spaced points, a receivy, er for converting the vibrations into electrical vibrations located at each of said points, 'a common recorder for all of said receivers. means associated with each receiver' for transferring energy to said recorder, and

means for blocking said transfer after an interval, comprising a condenser integrating the charges imparted thereto by the vibrations received by the receiver, and means wherebv the potential difference of the condenser is utilized to block said energy transfer.

7. In a svstem for recording earth vibrations at a plurality of spaced points. a receiv-l er for converting the vibrations into electrlcal vibrations located at each of said points,

a common recorder for all of said receivers, an electronic emission amplifier associated with each receiver for transferring energy to said recorder. and means for interrupting the How of energy between the amplifier and the 8. In combination, means sensitive to earthl y 4vibrations and adapted to convert the'same into electrical vibrations, means for transferring the electricalenergy from the sa1d 4- noname converting means to recording means, and means actuated by the arrival of continued and successive earth vibrations whereby the transfer of energy from said converting 5 means to said recording means may be interrupted.

9. The combination as set forth in claim 8, with the addition of means for adjusting the interval of interruption to any desired value l0 between the limits of operation.

10. The method of controlling the effective period of reception of a train of sound Waves, which comprises converting the sound waves into corresponding electrical vibratory energy, and dividing said energy between two electrical paths, storing the energy in one path to build up a predetermined potential, and stopping the How of energy in the other path when the predetermined potential is built up.

11. The method of controlling electrical energy in the form of electrical vibrations, which comprises amplifying said energy, storing energyin accordance With said vibra- 125 tions, and electrically blocking the amplification after a, predetermined energy is stored.

In testimony whereof I have hereunto set m hand. 4 i

y FR RIEBER. 

